feat(flex-stacker): stream motor driver stall guard value during move

[ahiuchingau]

This PR creates a freertos task that handles the streaming of the stall guard value if requested in the move. The stall guard result from the motor driver will be reported via a M900 message every 10 ms while the motor is in motion.

Any concerns regarding how the freertos task is created/executed?

[vegano1]

Thank you for setting this up and I'm glad it's working!

A few comments

1. It could get hard to manage multiple tasks from the same module, usually, we have one task per module. So if we want to go the new task route it would make sense to pull the run_stallguard_task into its own file that follows the motor_task.hpp and motor_driver_task.hpp framework.

2. Alternatively, instead of creating a new task, we could also use the freertos_timer.hpp to set up a timer from the motor_driver_task that calls read_stallguard and sends the result over USB. We use the timer with the Hepa/UV in the ot3-firmware repo, you can find that here.

[sfoster1]

10ms feels pretty fast for a text-mode UART but hey the math says it works so we good